With the bank preparing to go another round with the Hayne royal commission, the last thing it needed was a story revealing controls so lax that a fraud was being carried at the highest levels of the bank.

Relief shortlived

A heavily redacted follow-up report would appear to rule out most of these links, or confirm the bank no longer had ties to the introducers in question. But the relief was shortlived.

The same report would also reveal instances of NAB bankers helping customers forge documents, a banker accepting cash bribes and customers making a broad range of suspicious claims in supporting documents including childcare workers on preposterous salaries.

The key theme to emerge from the NAB case study and the banking royal commission in general is a failure to corroborate information. In the case of the alleged contractor fraud, however, there will be plenty of paperwork for investigators to cross check.

The strike force set up by NSW Police to investigate the allegations is still working its way through the assets and transactions of the parties involved following the raid on Tuesday morning.

This will include $6.5 million in proceeds from her sale of a five-bedroom Mosman mansion in the dying days of December last year. (The Australian Financial Review previously and incorrectly reported Rosamond had purchased the property on this date).

Popular choice

Rosamond bought the property for $4.2 million in 2012. It is understood the property was Rosamond's former marital home.

The assets of former NAB chief of staff Rosemary Rogers are also going under the microscope. Rogers, who resigned from the bank abruptly before Christmas, has amassed a hefty property portfolio including a rural retreat near Torquay and two Melbourne investment properties.

Rogers moved into her current residence in Williamstown earlier this year. She paid $3.8 million for the Victorian property, which includes an indoor pool featured in a climate-controlled pavilion and a veranda with tessellated tiles.

Williamstown has become an increasingly popular choice for home buyers in recent years with its vibrant cafe culture and marina. Strike Force Napthali is also believed to be looking into the purchase of a boat that is docked somewhere in Melbourne.

There are no bigger buzzwords in banking or business right now than "innovation" and "disruption". As banks look to reduce costs and mitigate risks, the bright lights of technology become increasingly alluring.

Martin Woods, the fraud expert and whistleblower who exposed the vast scale of money laundering at US bank Wachovia, says the same qualities are required of any effective compliance officer.

Confrontational and courageous

Good risk officers need the courage to be able to stick their noses where they aren't wanted, he says. They need to be confrontational and courageous.

If there is any good news to be found in all of this, it is that these problems were discovered at all.

Woods says whistleblowers need to consider the personal cost of calling out suspicious activity before following through, especially if the alleged offender is more senior than the whistleblower.

"Sometimes you have to cut the best deal for you and your family," Woods says.

"Fraud has been taking place at high levels of office for a very long time ... they can use that power to attack whistleblowers and keep the fraud buried."

In the alleged contractor fraud and the introducer program, authorities were tipped off following a report from bank employees.

NAB can take some comfort from the knowledge its whistleblower program appears to be working.